Baker — The Molluscan Fauna of Western New York. 83 



Superfamily Holopoda. 



Family Helicidae. 

 Genus Vallonia Risso. 



71. Vallonia pulchella Muller. 



Station 4. Pittsf ord ( Walton ) ; Cayuga ( Banks ) . Common 

 everywhere. 



72. Vallonia costata Muller. 



Station 21. Common and strongly ribbed. 



Genus Polygyra (Say). 1818; Pilsbry. 1889. 

 Section Mesodon Rafinesque. 



73. Polygyra albolabris Say. 



Stations 1, 5, 7, 13, 16 and 17. Rochester (Walton); 

 Cayuga (Banks). Very common. 



A form with a parietal tooth is found at Pittsf ord (var. 

 denlata of Walton's list). 



74. Polygyra thyroides Say. 



Stations 4, 11 and 18. Rochester (Walton); Cayuga 

 (Banks). Common everywhere. 



The young of this and the preceding species are very diffi- 

 cult, if not well-nigh impossible, to separate. 



75. Polygyra sayii Binney. 



Station 1. Pittsford (Walton); Cayuga (Banks). Ap- 

 parently quite rare. 



f76. Polygyra dentiferum Binney. 



Section Stenotrema Rafinesque. 



77. Polygyra hirsuta Say. 



Station 7. Rochester (Walton) ; Cayuga (Banks). Com- 

 mon. 



78. Polygyra Monodon Rack. Plate X. fig. 6. 

 Stations 1, 5 and 13. Rochester (Walton); Cayuga 



(Banks). A single specimen, from the Pinnacle, has two 



